1. Field of the Invention
The present invention relates generally to a communication system and a communication method thereof and, more particularly, to a radio frequency identification system including a reader and a tag, which share a predetermined secret key, and an authentication method thereof.
2. Description of the Related Art
In standard Radio Frequency Identification (RFID) technology, a tag includes specific tag information sent to a reader located within a certain distance. A reader can interpret tag information received from a number of tags, which are located in a proper range and even on the move, without contact with them. RFID systems are widely used in a variety of fields, such as payment by mobile phones, transportation payments, asset management and retail sales, product tracking, transportation and logistics, animal identification, inventory systems, libraries, human identification, and the like. Particularly, in most RFID systems, a tag or a reader is incorporated into communication terminals such as mobile devices.
A conventional RFID system may be susceptible to illicit attacks for gathering and cloning tag information by intervening upon a wireless communication between a reader and a tag. Therefore, in order to maintain security for tag information, a reader normally performs authentication of a tag before interpreting tag information. Specifically, a reader interprets tag information only after succeeding in authentication of a tag. A reader and a tag share at least one secret key and also exchange at least one random number so that a reader can authenticate a tag.